Every stage of a gas turbine engine must meet a plurality of design criteria to assure the best possible overall engine efficiency. The design goals dictate specific thermal and mechanical requirements that must be met pertaining to heat loading, parts life and manufacturing, use of combustion gases, throat area, vectoring, the interaction between stages to name a few. The design criteria for each stage is constantly being re-evaluated and improved upon. The high pressure turbine is subject to elevated temperatures and pressures, and as such adequate cooling must be provided to the elements of the high pressure turbine, including the turbine blades.